[PATCH][V3] iio: st_accel: fix iio_triggered_buffer_{pre,post}enable positions

[Alexandru Ardelean <alexandru.ardelean@analog.com>]

The iio_triggered_buffer_{predisable,postenable} functions attach/detach
the poll functions.

For the predisable hook, the disable code should occur before detaching
the poll func, and for the postenable hook, the poll func should be
attached before the enable code.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---

Changelog v1 -> v2:
* record the first error in st_accel_buffer_predisable() and return that 

Changelog v2 -> v3:
* move iio_triggered_buffer_postenable() after the allocation, but before
  `st_sensors_set_axis_enable()` based on comment from
  `Denis Ciocca <denis.ciocca@st.com>`

 drivers/iio/accel/st_accel_buffer.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/iio/accel/st_accel_buffer.c b/drivers/iio/accel/st_accel_buffer.c
index 7fddc137e91e..802ab7d2d93f 100644
--- a/drivers/iio/accel/st_accel_buffer.c
+++ b/drivers/iio/accel/st_accel_buffer.c
@@ -46,17 +46,19 @@ static int st_accel_buffer_postenable(struct iio_dev *indio_dev)
 		goto allocate_memory_error;
 	}
 
-	err = st_sensors_set_axis_enable(indio_dev,
-					(u8)indio_dev->active_scan_mask[0]);
+	err = iio_triggered_buffer_postenable(indio_dev);
 	if (err < 0)
 		goto st_accel_buffer_postenable_error;
 
-	err = iio_triggered_buffer_postenable(indio_dev);
+	err = st_sensors_set_axis_enable(indio_dev,
+					(u8)indio_dev->active_scan_mask[0]);
 	if (err < 0)
-		goto st_accel_buffer_postenable_error;
+		goto st_sensors_set_axis_enable_error;
 
 	return err;
 
+st_sensors_set_axis_enable_error:
+	iio_triggered_buffer_predisable(indio_dev);
 st_accel_buffer_postenable_error:
 	kfree(adata->buffer_data);
 allocate_memory_error:
@@ -65,20 +67,22 @@ static int st_accel_buffer_postenable(struct iio_dev *indio_dev)
 
 static int st_accel_buffer_predisable(struct iio_dev *indio_dev)
 {
-	int err;
+	int err, err2;
 	struct st_sensor_data *adata = iio_priv(indio_dev);
 
-	err = iio_triggered_buffer_predisable(indio_dev);
-	if (err < 0)
-		goto st_accel_buffer_predisable_error;
-
 	err = st_sensors_set_axis_enable(indio_dev, ST_SENSORS_ENABLE_ALL_AXIS);
 	if (err < 0)
 		goto st_accel_buffer_predisable_error;
 
 	err = st_sensors_set_enable(indio_dev, false);
+	if (err < 0)
+		goto st_accel_buffer_predisable_error;
 
 st_accel_buffer_predisable_error:
+	err2 = iio_triggered_buffer_predisable(indio_dev);
+	if (!err)
+		err = err2;
+
 	kfree(adata->buffer_data);
 	return err;
 }
-- 
2.20.1